Buggy code:
class TransactionSubsystem12Parser implements XMLStreamConstants , XMLElementReader < List < ModelNode > > , XMLElementWriter < SubsystemMarshallingContext > { public static final TransactionSubsystem12Parser INSTANCE = new TransactionSubsystem12Parser ( ) ; private TransactionSubsystem12Parser ( ) { } @ Override public void readElement ( XMLExtendedStreamReader reader , List < ModelNode > list ) throws XMLStreamException { if ( ( reader . getAttributeCount ( ) ) > 0 ) { throw unexpectedAttribute ( reader , 0 ) ; } final ModelNode address = new ModelNode ( ) ; address . add ( SUBSYSTEM , SUBSYSTEM_NAME ) ; address . protect ( ) ; final ModelNode subsystem = new ModelNode ( ) ; subsystem . get ( OP ) . set ( ADD ) ; subsystem . get ( OP_ADDR ) . set ( address ) ; list . add ( subsystem ) ; final ModelNode logStoreAddress = address . clone ( ) ; final ModelNode logStoreOperation = new ModelNode ( ) ; logStoreOperation . get ( OP ) . set ( ADD ) ; logStoreAddress . add ( LOG_STORE , LOG_STORE ) ; logStoreAddress . protect ( ) ; logStoreOperation . get ( OP_ADDR ) . set ( logStoreAddress ) ; list . add ( logStoreOperation ) ; final EnumSet < Element > required = EnumSet . of ( RECOVERY_ENVIRONMENT , CORE_ENVIRONMENT ) ; final EnumSet < Element > encountered = EnumSet . noneOf ( Element . class ) ; while ( ( reader . hasNext ( ) ) && ( ( reader . nextTag ( ) ) != ( XMLStreamConstants . END_ELEMENT ) ) ) { switch ( Namespace . forUri ( reader . getNamespaceURI ( ) ) ) { <START_BUG> case TRANSACTIONS_1_1 : <END_BUG> { final Element element = Element . forName ( reader . getLocalName ( ) ) ; required . remove ( element ) ; if ( ! ( encountered . add ( element ) ) ) { throw unexpectedElement ( reader ) ; } switch ( element ) { case RECOVERY_ENVIRONMENT : { TransactionSubsystem12Parser . parseRecoveryEnvironmentElement ( reader , subsystem ) ; break ; } case CORE_ENVIRONMENT : { TransactionSubsystem12Parser . parseCoreEnvironmentElement ( reader , subsystem ) ; break ; } case COORDINATOR_ENVIRONMENT : { TransactionSubsystem12Parser . parseCoordinatorEnvironmentElement ( reader , subsystem ) ; break ; } case OBJECT_STORE : { TransactionSubsystem12Parser . parseObjectStoreEnvironmentElementAndEnrichOperation ( reader , subsystem ) ; break ; } case JTS : { parseJts ( reader , subsystem ) ; break ; } case USEHORNETQSTORE : { parseUsehornetqstore ( reader , logStoreOperation ) ; subsystem . get ( USEHORNETQSTORE ) . set ( true ) ; break ; } default : { throw unexpectedElement ( reader ) ; } } break ; } default : { throw unexpectedElement ( reader ) ; } } } if ( ! ( required . isEmpty ( ) ) ) { throw missingRequiredElement ( reader , required ) ; } } private void parseJts ( final XMLExtendedStreamReader reader , final ModelNode operation ) throws XMLStreamException { } private void parseUsehornetqstore ( final XMLExtendedStreamReader reader , final ModelNode operation ) throws XMLStreamException { } static void parseObjectStoreEnvironmentElementAndEnrichOperation ( final XMLExtendedStreamReader reader , ModelNode operation ) throws XMLStreamException { } static void parseCoordinatorEnvironmentElement ( final XMLExtendedStreamReader reader , final ModelNode operation ) throws XMLStreamException { } static void parseCoreEnvironmentElement ( final XMLExtendedStreamReader reader , final ModelNode operation ) throws XMLStreamException { } static void parseProcessIdEnvironmentElement ( XMLExtendedStreamReader reader , ModelNode coreEnvironmentAdd ) throws XMLStreamException { } static void parseSocketProcessIdElement ( XMLExtendedStreamReader reader , ModelNode coreEnvironmentAdd ) throws XMLStreamException { } static void parseRecoveryEnvironmentElement ( final XMLExtendedStreamReader reader , final ModelNode operation ) throws XMLStreamException { } @ Override public void writeContent ( XMLExtendedStreamWriter writer , SubsystemMarshallingContext context ) throws XMLStreamException { } private void writeProcessId ( final XMLExtendedStreamWriter writer , final ModelNode value ) throws XMLStreamException { } }

Fix:
case TRANSACTIONS_1_2 :